This repository is a TypeScript monorepo of 40+ markdown-it plugins, published as individual @mdit/plugin-* npm packages plus the @mdit/helper utility package. It is a developer-facing library ecosystem, not an application: each plugin extends markdown-it with additional Markdown syntax and rendering behavior, including alerts, containers, tabs, footnotes, task lists, definition lists, abbreviations, emoji, math (KaTeX and MathJax with full and slim variants), diagrams (PlantUML/UML), image controls (size, lazyload, mark), advanced links, attribute syntax, icons, layout directives (flex/grid/columns), file include/snippet (Node-only, file-system based), and text semantics (sub, sup, mark, ins, ruby, spoiler). The plugins are consumed primarily by static-site generators such as VuePress/VitePress and by any Node or browser pipeline that renders Markdown via markdown-it.